Comparison with the OGC Simple Feature Access Definition

The OGC Simple Feature Access definition is a fundamental definition of geospatial features, adapted widely by geospatial software users and vendors alike. The definition is centered around the concept of "simple features".

An OGC Simple feature is defined as "(...) a 2D geometry with linear interpolation between vertices"¹. By comparison, a XFM feature is not limited to 2D or linear elements.

This a comparison of the XFM Feature and OGC Simple Feature geometry types:

XFM Feature Geometry Type	OGC Feature Geometry Type	Remarks
point-cell	Point	A XFM point-cell with the default cell is a valid representation of an OGC Point.
collection-point-cell	MultiPoint	-
point-text	-	The OGC Simple Feature Access definition does not support annotations or cartographic text.
collection-point-text	-	See previous remark.
linestring/curve	LineString (Line, LinearRing)	Note that an OGC LineString is a subset of a XFM linestring/curve. If a XFM client is to be compatible with OGC Simple Features, it should exclude placement and modification methods that support arcs, b-splines or curves.
collection-linestring/curve	MultiLineString	An OGC MultiLineString is a subset of a XFM collection-linestring/curve.
polygon	Polygon	An OGC Polygon is a subset of a XFM polygon.
collection-polygon	MultiPolygon	An OGC MultiPolygon is a subset of a XFM collection-polygon.

Note: In addition to the remarks above, compatibility with OGC Simple Features also implies that XFM features should be limited to 2D features

OpenGIS(r) Implementation Specification for GeoGraphics Information - Simple feature access - Part 1: Common architecture.